Monitoring benthic foraminiferal dynamics at Bottsand coastal lagoon (western Baltic Sea).

They were monitored annually in late autumn since 2003 at the terminal ditch of the lagoon. There were 12 different species recognised, of which three have not been recorded during earlier investigations.

Dom- inant species showed strong interannual fluctuations and a steady increase in population densities over the last decade. Elphidium incertum, a stenohaline species of the Baltic deep water fauna, colonised the Bottsand lagoon in 2016, most likely during a period of salinities >19 units and water temperatures of 18 C on average in early autumn. The high salinities probably triggered their germination from a propagule bank in the ditch bottom sediment.